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digitalmars.D.learn - Sending messages using socket

reply nrgyzer <nrgyzer gmail.com> writes:
Hi guys,

I'm trying to work with sockets but I've some trouble with them. I
implemented a really simple Socket which should simply send a text
message after accepting the request. My code is the following:

module server;

import std.socket;

void main() {

	TcpSocket server = new TcpSocket();
	server.bind(new InternetAddress(8080));
	server.listen(1);

	while(true) {
		Socket cs = server.accept();
		cs.send("test");
	}

}

When I start my small sample application and tries to connect (http://
localhost:8080) to them using a browser I don't get any message. It
seems to work forever and sometimes I get my message "test", but the
connection between my browser and my application won't finished.
When I add cs.close() after cs.send("test"), the connection will be
closed, but I don't get any message in my browser - the browser says
that the service isn't available (error-page).

What's wrong with my code? => Thanks for any help :)
Jul 24 2011
parent reply Adam Ruppe <destructionator gmail.com> writes:
Browsers speak HTTP, which is a higher level protocol than
plain sockets.

If you connect to your app with a simpler program, like nc,
you'll probably see the message.

If you want to serve web pages, consider one of these options:

a) Looking up the HTTP protocol itself. You've gotta send headers
before you send data or the browser won't understand what you are
replying to.

b) Use an existing web server, like Apache, and write your app as
a cgi program



The HTTP headers you need to send on a plain socket look like this:

=====
HTTP/1.0 200 OK
Content-Length: 11
Content-Type: text/html

hello world
=====

instead of just plain "hello world".
Jul 24 2011
next sibling parent nrgyzer <nrgyzer gmail.com> writes:
== Auszug aus Adam Ruppe (destructionator gmail.com)'s Artikel

 Browsers speak HTTP, which is a higher level protocol than
 plain sockets.
 If you connect to your app with a simpler program, like nc,
 you'll probably see the message.
 If you want to serve web pages, consider one of these options:
 a) Looking up the HTTP protocol itself. You've gotta send headers
 before you send data or the browser won't understand what you are
 replying to.
 b) Use an existing web server, like Apache, and write your app as
 a cgi program
 The HTTP headers you need to send on a plain socket look like this:
 =====
 HTTP/1.0 200 OK
 Content-Length: 11
 Content-Type: text/html
 hello world
 =====
 instead of just plain "hello world".


Great - works, thanks :)
Jul 24 2011
prev sibling parent nrgyzer <nrgyzer gmail.com> writes:
== Auszug aus Adam Ruppe (destructionator gmail.com)'s Artikel

 Browsers speak HTTP, which is a higher level protocol than
 plain sockets.
 If you connect to your app with a simpler program, like nc,
 you'll probably see the message.
 If you want to serve web pages, consider one of these options:
 a) Looking up the HTTP protocol itself. You've gotta send headers
 before you send data or the browser won't understand what you are
 replying to.
 b) Use an existing web server, like Apache, and write your app as
 a cgi program
 The HTTP headers you need to send on a plain socket look like this:
 =====
 HTTP/1.0 200 OK
 Content-Length: 11
 Content-Type: text/html
 hello world
 =====
 instead of just plain "hello world".


The message exchange works, but I've some trouble in getting the messages
correctly. I've the following, small apps:

module server;

import std.socket;
import std.stream;
import std.socketStream;

void main() {

	TcpSocket s = new TcpSocket();
	s.bind(new InternetAddress(5088));
	s.listen(1);

	while(true) {

		Socket a = s.accept();
		SocketStream cs = new SocketStream(a);

		string response = "HELLO WORLD!";
		cs.writeBlock(response.ptr, response.length);

		a.close();

	}

}

module client;

import std.socket;
import std.math;
import std.stream;
import std.socketStream;
import std.stdio : writeln;

void main() {

	TcpSocket s = new TcpSocket();
	s.connect(new InternetAddress("127.0.0.1", 5088));

	while(true) {

		void[] msg;
		SocketStream cs = new SocketStream(s);
		cs.readBlock(msg.ptr, 12);
		writeln(msg);

	}

}

But... when I start the server and client, I don't get any response/and or my
message is empty. When I use the simply methods of streams
(like write()), it works but the problem is, that the following will end in an
endless loop:

module client;

import std.socket;
import std.math;
import std.stream;
import std.socketStream;
import std.stdio : writeln;

void main() {

	TcpSocket s = new TcpSocket();
	s.connect(new InternetAddress("127.0.0.1", 5088));

	while(true) {

		uint len;
		string msg;
		SocketStream cs = new SocketStream(s);
		while(!cs.eof()) { // this loop repeats forever, although the stream is empty
			cs.read(len);
			cs.readString(msg, len);
		}

	}

}
Jul 25 2011